Cardiomyopathy Flashcards
What are the major risk factors for sudden cardiac death in HOCM?
Major risk factors for SCD in HCM are
- severe LVH (>30mm)
- unexplained syncope
- personal/family history of sudden cardiac arrest
- documented NSVT.
Abnormalities seen in postural orthostatic tachycardia
- The key abnormality in postural orthostatic tachycardia syndrome is that the HR should markedly and
exaggeratedly increase on standing. - The typical cut-off criteria are that HR should increase >30 beats/min or to >120bpm on standing, without any significant postural hypotension.
What should you be concerned about if a patient has ongoing symptoms despite treated pericarditis
- Constrictive pericarditis is a really important diagnosis to consider in the patient whose symptoms
don’t settle post resolution of pericarditis. - Suggestive clinical features are recurrent presentations with right heart failure (development of constrictive physiology increasing back-pressure) and development
of pericardial calcification. - Specific diagnosis is made on echocardiography which will show haemodynamic features of constriction (ventricular interdependence, annulus reversus, hepatic vein reversal during diastole in expiration etc). Treatment is initially medical (steroids, re-challenge with
anti-inflammatories), but patients may ultimately require pericardiectomy
What infections cause myocarditis?
The most common causes are adenovirus, coxsackievirus, and enterovirus (ACE)
HOCM
- Mode of inheritance
- Pathophysiology
Autosomal dominant with high disease penetrance
- Diastolic dysfunction and dynamic left ventricular outflow tract obstruction
- Dynamic LVOT obstruction is exacerbated by any therapy that increases contractility, eg: digoxin or other inotropic agents
- Worsened by reduced ventricular preload, eg: dehydration
HOCM symptoms
- Most patients with HCM have minimal or no symptoms.
However, a subset develop
- exertional dyspnea
- angina
- presyncope, or syncope.
- Sudden cardiac arrest may be the initial manifestation of the disorder.
HCM accounts for approximately 35% of sudden deaths among all persons younger than 35 years and is the leading cause of sudden death in this
age group.
Examination findings of HOCM
- Ejection systolic murmur over left lower sternal murmur
- Augmentation of the murmur occurs during maneuvers that decrease preload (swuat to stand, valsalva)
Note: AS and MR decrease with maneuvers that reduce preload
Ix for HOCM
ECG: left ventricular hypertrophy
TTE: LVOT obstruction gradient >30 at rest or >50 with provocation
Diastolic dysfunction but normal systolic function
asymmetric hypertrophy of the interventricular septum
Indications for ICD in HOCM
Placement of an implantable cardioverter defibrillator should be considered in patients with hypertrophic cardiomyopathy with one or more major risk factors for sudden cardiac death:
- prior cardiac arrest
- massive myocardial hypertrophy
- family history of sudden cardiac death
- ventricular tachycardia
- blunted blood pressure response to exercise
- unexplained syncope
Management of HOCM
- The major management goals for patients with HCM are alleviation of symptoms, risk stratification for sudden cardiac death,
ICD implantation for those at high risk, and family counseling. - Abstain from competitive sports or strenuous
aerobic activities is advised for all patients. - Avoid dehydration and states of severe peripheral vasodilatation, such as from hot baths or saunas.
- Pregnancy generally is well tolerated, although
precautions should be taken to minimize peripheral vasodilatation as for all patients with HCM.
Pharmacological agents for HOCM
Negative inotropic agents are the cornerstone of medical therapy for patients with symptomatic obstructive HCM
- B blockers
- Nondihydropyridine calcium channel blockers
- verapamil
- Disopyramide
They all depress contractility, thereby reducing the intraventricular flow velocities that predispose
to LVOT obstruction. These agents also lengthen diastole, facilitating more time for ventricular filling.
What medications should be avoided in HOCM
Positive inotropes (such as digoxin), vasodilators, and high dose diuretics should be avoided, as these drugs exacerbate LVOT obstruction
Nitrates
ACEi
Surgery for HOCM
- For patients with persistent, severe, drug-refractory symptoms caused by obstructive HCM, septal reduction therapy with surgical septa! myectomy or percutaneous alcohol septal ablation
should be considered.
Surgical myectomy is the gold standard therapy for relief of LVOT obstruction.
Need to screen first degree relatives
Difference between dilated, hypertrophic and restrictive cardiomyopathy
DILATED
- Major Abnormality: impaired contractility
- Wall thickness: usually low, normal
- Dimensions: left ventricle dilation
- EF: reduced - systolic dysfunction with normal diastole
HYPERTROPHIC
- Major Abnormality: impaired relaxation
- Wall thickness: increased ++
- EF: normal in early stages
RESTRICTIVE
- Major Abnormality: impaired elasticity
- Wall thickness: usually usually increased +
- Dimensions: normal
- EF: Normal
Features of dilated cardiomyopathy
- Thin ventricular walls, left ventricle dilation, decreased EF (systolic dysfunction with normal diastole)
- Most common subtype - 90%
Mainly are idiopathic Secondary Causes - Ischaemic cardiomyopathy - Toxins/cocaine abuse - Nutritional deficiencies, eg: thiamine deficiency (beri-beri) or selenium deficiency - Myocarditis: inflammation of the heart muscle Viruses (eg: Coxsackie B) Autoimmune Disease (eg: Lupus)
systolic murmur: stretching of the valves may result in mitral and tricuspid regurgitation
